1. 1. A cylindrical, usually metal casing containing the primer and charge of ammunition for firearms.
   2. Such a casing fitted with a bullet.
   3. A similar piece of ammunition, such as a shotgun shell.
2. A case filled with high explosives, used in blasting.
3. A small modular unit designed to be inserted into a larger piece of equipment: an ink cartridge; a disposable cartridge of caulking compound.
4. A removable case containing the stylus and electric conversion circuitry in a phonograph pickup.
5. 1. A case containing magnetic tape in a reel; a cassette.
   2. A case containing a ribbon in a spool, for use in printers and electric typewriters.
6. A lightproof case with photographic film that can be loaded directly into a camera.

[Alteration of earlier cartage, alteration of French cartouche, from Italian cartuccio, variant of cartoccio, roll of paper. See cartouche.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.